Problem: Simplify the following expression: $y = \dfrac{-8n}{10} - \dfrac{10n}{10}$
Explanation: Since the expressions have the same denominator we simply combine the numerators: $y = \dfrac{-8n - (10n)}{10}$ Combine like terms: $y = \dfrac{-18n}{10}$ Simplify by dividing numerator and denominator by 2: $y = \dfrac{-9n}{5}$